1. The Field of the Invention
The invention relates to medical systems, methods, and devices, more specifically, the invention relates to a fluid sampling system.
2. Relevant Technology
In some medical procedures, the condition of a patient can require that an intravenous/intra-arterial tube or catheter be inserted into a blood vessel. The patient's blood vessel can be connected by the tube to a source of fluid which can provide fluid, such as a medicament, and which can also be connected to a pressure transducer that senses the pressure within the patient's blood vessel.
In critical care situations, it can be necessary to periodically obtain samples of the patient's bodily fluids, such as blood. For procedures carried out using a needle stick, the likelihood of a health care worker being inadvertently stuck can increase, thereby increasing the risk of infection from a contaminated needle. Rather than stick a patient with a needle each time blood must be drawn, blood can be drawn through the tube already connected to the patient's blood vessel. Since the tube connected to the patient's blood vessel can contain fluid other than blood, such as saline solution and some medication, it is useful to draw the patient's blood up into the tube so that a blood sample can be obtained which is substantially unadulterated by the fluid which is being supplied to the tube by an external source. After the substantially unadulterated blood has been drawn up the tube to a sampling site, the blood sample can be collected into a sample container.
Disadvantageously, many of the previously available devices require two-handed operation by a medical practitioner. Some of the previous devices utilize a conventional medical syringe to create the suction necessary to draw the blood up the tube. Such syringes are often unwieldy to use and their typical long, narrow dimensions makes them cumbersome. Many of the previously available devices are complicated and expensive. Moreover, some of the previously available devices include sharp bends in the fluid path and/or relatively long supplementary fluid paths both of which result in residual blood and fluid remaining in the fluid path which can cause problems such as clotting.
In 2001, a study of 1548 patients was performed to demonstrate the effects of “intensive insulin therapy” on mortality and morbidity. See Greet Van den Bergh, et. al., Intensive Insulin Therapy in Critically Ill Patients, The New England Journal of Medicine, Vol. 345:1359-1367, No. 19, Nov. 8, 2001. The study showed that patients with tightly controlled blood glucose levels (between 80-110mg/dl) had remarkably improved outcomes. Overall mortality was decreased by 34%, blood stream infections by 46%, acute renal failure requiring dialysis or hemofiltration decreased by 41%, the median number of red cell transfusions decreased by 50% as well as requiring less time on the ventilator and less days in the ICU. Beyond the increased health benefits to patients, this reduces hospital costs by $3000 to $4000 per ICU patient. See http://www.santacruzsentinel.com/archive/2005/February/13/biz/stories/02biz.htm.
The medical community has been striving for successful implementation of intensive insulin therapy because of the documented benefits of intensive insulin therapy. In order to implement this therapy, patients can have their fingers stuck for glucose readings every hour for days, weeks and even months. This has caused a significant amount of pain and torment to be inflicted to the patients. Additionally, repeated glucose level monitoring can take up valuable time of registered nurses (RNs) and practitioners.